In comparison with existing distance-based methods such as [1]}, [2]}, [3]}, which use single- or double-integrator dynamics for the system, the novelty of this paper is a study of a general class of nonlinear systems with unknown nonlinearity, time-delay on the dynamical states, and disturbance. The formation control problem of nonlinear multi-agent systems with state time-delay function is studied in [4]}, [5]}, [6]}, [7]}, where the authors consider a bounded time-delay for a nonlinear multi-agent system. In contrast with these methods where the Laplacian matrix is used to express the relation among the agents, our control law is based on rigid graph theory. While the formation control problems can be modeled with standard graph theory, a rigid graph theory offers modeling that minimizes the number of edges/distances that one needs to control in order to achieve the desired formation.
